1. Field of the Invention
The present invention relates to highly dispersible inorganic compound nanoparticles having good dispersibility which bond to various functional molecules, and a method of production thereof.
2. Description of the Prior Art
Recently, nanotechnology research has been widely carried out and atomization (nanoparticle-formation) processes of many kinds of substances used as materials are being researched in various industrial fields. Because such nanoparticle-formed materials show an improvement of flowability, an increase in surface area and an enhancement of reactivity on the surface, by applying such a change of physical properties, an improvement in density at the time of compression molding, an increase in adsorption capacity, an improvement of a function as a chemical reaction catalyst and the productivity of a composite with other materials can be achieved easily. The functionalization of nanoparticles to other materials by mixing or forming a composite with other materials is commonly applied in the fields of coatings, surface modification materials, cosmetics, high refraction index glasses, ceramics, strong magnetic materials and semiconductors materials, etc.
Accordingly, nanoparticle formation of substances has become extremely important technology, and there are prospects for application thereof to the fields of chemistry, biochemistry, molecular biology and medical science. Recently, experiments have been made with very small particles being combined with a labeled compound to identify, detect, quantify and visualize a specific molecular structure. Calcium phosphate compound and silica which have very excellent stability at the time of preservation and are harmless to a living body are used as particles. If such particles can be used in nanoparticle form, it is possible to combine them with much more labeled compound molecules so that a large improvement in sensitivity is achievable.
For example, a protein is impossible to be visually observed because they are transparent in a solution except special examples such as some colored proteins. Additionally it is difficult to detect only a specific protein in the state where many substances are intermingled. Therefore some solution procedures such as binding the protein with pigment molecules having specific optical characteristics, labeling with a radioisotope, or binding other enzymes have been developed, and the detection and quantification of the target protein in the mixture are carried out. These solution procedures are used abundantly for the purpose of identifying, detecting and quantifying not only the protein but the target substance in a solution series or an internal environment of a live body in which DNA, RNA and sugars, etc., are intermingled.
In the case where these labeled molecules are antigens, antibody proteins, sugars, receptors, ligands, nucleotides, etc., which recognize a specific molecular structure, these substances are used for identifying, detecting, quantifying and visualizing a certain molecular structure. In the case where the labeled substance is detected and quantified spectroscopically, labeling by a radioisotope was performed in the past, however, recently coloring matters are often utilized (color labeling method). When the concentration of a labeled compound is low, labeling with an enzyme, etc., is performed to carry out a converting reaction of the substrate with a small quantity of enzyme over a long period of time to make detection possible (enzyme labeling method).
Furthermore, a labeling method with very small particles, which is a recent trend, has attracted considerable attention due to a labeling compound such as a coloring matter being able to be accumulated in a particle at a high concentration using very small particles.
However, because inorganic compound nanoparticles have a strong aggregation property in a solution, when the surfaces of the particles are covered with the labeled compounds, the aggregation property thereof is strengthened, so that the particles become bulky causing deterioration of sensitivity.